The present invention relates generally to machines for successively forming helical coil springs each consisting for successively forming tension, compression or torsion helical coil springs consisting of a body portion having a number of loops and opposite end loops for attachment. More particularly, the present invention relates to machines in which a wire guide member having a longitudinal groove or quill through which a length of wire is forcibly fed from a supply reel thereof employs a tool member having a tapered free end adapted to be radially movable timingly between a retracted position and an advanced position where the tapered end engages the wire emerging from the quill for bending and coiling to form the leading end loop portion, then the coiled body portion and finally the trailing end loop portion.
Various machines of the type as referred to above have been proposed. For example, U.S. Pat. No. 3,025,889 discloses a machine in which a quill is provided with a coil receiving void at one side thereof so as to be substantially in the form of a longitudinally cut half cylinder. As well known by those skilled in the art, a void is necessary for permitting the formed coil body portion to locate there while the end loop portion is being formed. Since the metal wall thickness between the void surface and the longitudinally extending groove or quill formed in the solid guide member must be fairly thin, the wall is easily broken at the wire output end of the quill when bending wire of a large diameter through a large angle such as 90.degree..
Machines according to the prior art can practically produce coiled springs from wire having a diameter generally up to the order of about 1 mm. It is often necessary, however, to make springs from wire having a diameter on the order of from a few to several mm. Hitherto, the end loops of such coil spring have had to be formed by a separate tool or machine in order to avoid breaking the thin wall of the quill. Thus, either the straight wire portion connected to the coil body or the outermost of the coils of the coil body formed by conventional coiling machines inclusive of the machine referred to above, requires subsequent mandrel-die bending operations to complete the spring.